Identification of BY Draconis Variable Stars in ASAS Data
Abstract
A spreadsheet of 3,548 automatically classified candidate Cepheid variable stars in the ASAS (All Sky Automated Survey) photometry data was provided to members of the AAVSO (American Association of Variable Star Observers) for analysis. However, it was known from the start that the computer filters had overpopulated the list, for example including Beta Cepheid stars in addition to Type I and Type II Cepheids. Patrick Wils investigated a small subset of the data using 2MASS, PPMXL, and ROTSE data and discovered that the vast majority of the 84 candidates he surveyed appeared to have been misidentified. The most common misidentification seemed to be of BY Draconis stars (spotted K and M dwarfs). In addition, since the light curves of Type II Cepheids are especially ambiguous in certain period ranges, this automatic classification of large photometric surveys is especially problematic for researchers seeking examples of this rarer type of star. The ongoing project described here is a systematic identification of candidate BY Draconis stars from among the 3,548 original candidates. The stars are being sorted using VSX (International Variable Star Index) information, for example to search for prior identification by other authors in the time since the initial population of the candidate list (as has been done using ROTSE data), along with infrared photometry (2MASS) and proper motion (PPMXL) data. An analysis of light curves and phase plots is the final step in identifying potential BY Draconis stars. The goal of this project is to submit updated identifications for these stars to the International Variable Star Index (VSX).
- Publication:
-
American Astronomical Society Meeting Abstracts #223
- Pub Date:
- January 2014
- Bibcode:
- 2014AAS...22315604L